Connector and method

ABSTRACT

A tubular body section having threads attached at one end and a nut held captive on the other end with a tool engaging portion attached intermediate the threads and nut and a method of making the foregoing including the steps of forming the tubular body section from sheet metal, positioning the tool engaging portion on the tubular body section, providing a thread form on the tubular body section adjacent one end thereof, brazing the parts together, thereafter positioning the nut on the other end of the tubular body section and deforming said other end of said tubular body section to hold the nut captive.

United States Patent 1 Metcalf [111 3,729,217 [451 Apr. 24, 1973CONNECTOR AND METHOD [75] Inventor: Irving R. Metcalf, St. Charles, [11.[73] Assignee: Ideal Industries, Inc., Sycamore, I11. [22] Filed: May10, 1971 [21] App]. No.: 141,727

[52] U.S. Cl. ..285/183, 29/456, 29/470.5,

- 29/463, 29/437, 285/286, 285/390 [51] Int. Cl ..F16l 15/00 [58] Fieldof Search ..285/340, 424, 183,

285/39, 286, 175, 212, 386, 333, 355, 342; 29/157 R, 157 A, 437, 470.5,456, 463; 85/32 LS, 36; 138/171 1 56] References Cited UNITED STATESPATENTS FOREIGN PATENTS OR APPLICATIONS Germany ..285/39 Sweden ..29/456Primary ExaminerDave W. Arola AttorneyHoward T. Markey et a1.

[57] ABSTRACT A tubular body section having threads attached at one endand a nut held captive on the other end with a tool engaging portionattached intermediate the threads and nut and a method of making theforegoing including the steps of forming the tubular body section fromsheet metal, positioning the tool engaging por tion on the tubular bodysection, providing a thread form on the tubular body section adjacentone end thereof, brazing the parts together, thereafter positioning thenut on the other end of the tubular body section and deforming saidother end of said tubular body section to hold the nut captive.

12 Claims, 6 Drawing Figures Patented April 24, 1973 3,729,217

A ,F/l/g/MA 5% f/l/Q/ 17/4 7 I CONNECTOR AND METHOD SUMMARY OF THEINVENTION This invention is concerned with a method and procedure formaking a structure for a flexible conduit connector or any threadedfitting and the connecter produced thereby.

A primary object is a connecter for joining flexible conduit thatcontrols and insures the wall thickness under the threads.

Another object is a method of making such connecter which does notproduce any chips in forming the threads.

Another object is a connecter assembly which is selfjiggering in thesubsequent furnace brazing operation during its manufacture.

Another object is a method of making pipe threads that is inexpensive.

Another object is a flexible conduit connecter and method of making itwhich does not require any castings.

Another object is a method and connector of the above type which resultsin a connecter with a clean surface having no residual fluidaccumulations which must be removed for plating and corrosionresistance.

Another object is a connector of the above type which can be made in aseries of press operations followed by furnace brazing.

Another object is a method of making a connector of the above type whichdoes not require any thread rolling or thread cutting which is quiteexpensive.

Another object is a method of making threads on a connecter of the abovetype which guarantees a certain wall thickness under the threads.

Another object is a method of making a tapered pipe thread in a furnacebrazing operation which insures a tight joint.

Another object is a method and connecter of the above type whichcompletely eliminates any castings thereby cutting down on scrap andtool loss.

Another object is a fitting and method of the above type which gives aferrous product without any casting and a minimum of machining.

Another object is a method and connecter of the above type made onspring coiling and stamping equipment.

Other objects will appear from time to time in the ensuing specificationand drawing in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side view, partly insection, showing one form of the invention;

FIG. 2 is a bottom view of FIG. 1;

FIG. 3 is a section along line 33 of FIG. I;

FIG. 4 is an enlarged view, partly in section, of the coil;

FIG. 5 is a side view, partly in section, of a variant form; and

FIG. 6 is a section through a variant form of thread formation.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 a connecter isindicated generally at 10 in the form of an elbow with a body section 12made of two halves 14 and 16, one of the halves 16 having flanges oroffsets 18 which overlap the abutting edges of the other half 14.Otherwise, the two halves are mirror images of each other and can bemade from sheet metal suitably formed as stampings on conventionalpresses, for example progressive die or transfer presses. The ends ofeach half are tapered somewhat as at 20 and the overlapping flange oredge 18 on the one half terminates as at 22. Thus, the areas of theabutting edges in the tapered portion 20 are directly abutting with nooverlap. The flanges or overlap 18 also terminate at the other end as at24 in spaced relation to the end 26 so that a sleeve or ring 28 may beslipped on and preliminarily positioned against the edge 24 of theoverlap or flange. While the ring 28 has been shown as flared out as at30, it is initially a simple sleeve or ring or cylinder and the flare 30is caused later.

An octagonal body 32 which is cylindrical on the inside at 34 andoctagonal on the outside at 36 may be stamped or formed from the sheetmaterial and then slipped over the taper 20 until it abuts the edge 22of the flange or overlap 18.

A thread formation 38 is formed on the taper by coiling a wire 40 ofsuitable length into a generally cylindrical coil and then slipping itover the taper 20. The wire is shown as having a triangular crosssection 42 with one flat side 44 being disposed on the inside of theresulting coil so that the inner surface of the coil presents a smoothcylindrical appearance with the outer edge or point 46 of the triangularforming the crest of the resultant threads. Wire that is triangular incross section is particularly appropriate since the sides or flanks ofthe threads resulting from the triangle will be at 60, which isappropriate for pipe threads.

The wire can be coiled to an internal diameter which is slightly smallerthan the maximum outside diameter of the taper 20 so that when thecylindrical inner surface of the coil is slipped onto the taper, thecoil will be expanded somewhat throughout its length, thereby giving aslight compression or loaded fit. Since the exterior of the taperincreases in diameter from the end, the coil will be progressivelyexpanded from the small end up. But the degree of interference should besufficiently small such that no great effort is necessary to assemblethe two.

Assembly is as follows: The two halves l4 and 16 are brought together,the sleeve 28 is slipped on along with the octagon 32 and the coil 40,all three of which hold the two halves together and properly positionedwith their edges abutting. In this form, the unit can be furnace brazedwhich will seal together the abutting edges of the two halves l4 and 16,will seal the sleeve 28 on one end of the resulting elbow, will seal theoctagon in place, and will fuse the inner surface 44 of the coil fullyand completely to the exterior of the taper 20. After removal andcooling, a nut 48 with internal threads 50 and a flange or shoulder 52at one end is slipped over the sleeve 28. And the sleeve is flared orbelled out as at 30.

A'variant form is shown in FIG. 5, which is straight instead of an elbowlike in FIG. 1. The parts and procedure may be the same except that thebody 54 is made of a straight tubular section and not two halves, as inFIG. 1. The body may be stamped or drawn from a sheet with a taperformed at one end, as at 56, with the coil shown thereon to be formed,positioned. and

brazed in the same manner as described in connection with FIG. 1. Theoctagon 58 may also be the same. After furnace brazing, a nut 60 may beslipped on the other end and that end flared or belled as at 62 to holdthe nut in place.

In FIG. 6, a variant form has been shown in which a thread formation64-is formed from a single piece of aluminum or the like suitably pulledor pressed into the thread form shown on a slight taper to match thetaper of end or 56. The rolled thread 64 might be used as a substitutefor the coiled thread 40 in certain applications and could be applied,brazed and used in the same manner.

The use, operation and function of the invention are as follows:

Connecters for joining flexible conduit to junction boxes and the likein the past have taken the form of castings which have the disadvantagethat, first, they are difficult to clean and threads must be machined onthem; second, they have a very dull finish; third, they are veryexpensive; fourth, after machining they require a thorough cleaning sothat all metal chipswill be removed; fifth, they must be made onexpensive equipment, such as screw machines and the like; and, sixth,they do not insure a uniform wall section under the machine threadswhich results in high loss due to scrapsand rejects.

The present connecter has the advantage that all parts can be formed ofstampings made on conventional presses. In the form of FIG. 1, the twohalves can be made on a simple transfer press as can the octagon andsleeve. The triangular wire can be formed on simple spring coilingequipment. The parts can be all brought together with the sleeve,octagon and wire coil automatically fixturing the two halves in thebrazing furnace. In the resultant product, the thickness of the wallunder the threads 38 in the taper 20 will be known and insured. Thus,there will be a minimum of scrap. Also the parts will have an extremelybright finish which results in a very goodlooking final product. All ofthe joints that are brazed are not required to be metalto-metal at allpoints since the braze will fill small gaps. This is true under the coiland between the abutting edges of the two halves and under the sleeve28. While I have said that the triangular wire is wound to a straightcylinder,,it might also have a slight taper, and the braze will fill anygap between the tapered exterior surface 20 and the cylindrical side 44of the triangular cross section.

In prior constructions, a straight tube has been bent for the elbow. Butthis has the disadvantage that tubing can only be bent to a certainminimum radius. In the present form where two halves are broughttogether and the entire assembly brazed, the minimum radius can be verysmall. Thus, an elbow connecter with a quite small radius will result.While I have shown an overlap 18 between the two halves l4 and 16, itshould be understood that it may be a straight butt joint, abuttedflange, or interpenetrating teeth with any suitable interlocking edge orsome combination. thereof. The materials need not be all the samethickness, but the thinnest materials should be on the inside so thatthey will tend to expand faster against the pieces pressed over theouter surfaces in order to prevent looseness while heating.

Of particularimportance is'the fact that there is no need to fixture aunit before furnace brazing because the outer parts mechanically forcethe inner parts together and hold them in place. The present inventioncompletely avoids all of the problems of making castings with a uniformwall thickness and the difficulties of' machining malleable iron whichinevitably results in a high scrap and tool loss rate. I also avoidhaving to use nonferrous metals. In certain types of application, thetwo halves of the body section might be mirror images so that only onepress die is required. If desired, a suitable O-ring and retainer mightbe positioned against the octagon 32 around the threads. But this isoptional.

Some of the main advantages offorming threads this way is that no chipsare produced which means no cleanup. You can form the thread right up toits shoulder which is extremely difficult to do in machine threads andis very expensive. We can quite accurately control the wall thicknessunderneath the threads which is extremely difficult, if not impossible,when cutting or rolling threads due to the eccentricity of the partsinvolved.

Another advantage is that the entire fitting is made of a minimum numberof parts. For example, the FIG. 1 form has five parts, the two bodyhalves, the coil, the octagon, and the sleeve. The FIG. 5 form only hasthree parts, the single body form, the coil and .the octagon. The nut ineach case is considered separate since it is put on later after furnacebrazing.

The FIG. 1 form has the advantage that assembly is simple and does notrequire accurate spacing. The octagon is slipped on the tapered enduntil it abuts the ends 22 of the overlap 18. The coil 40 is slipped onthe taper until it hits the octagon. The sleeve 28 at the other end isslipped on the end of the two halves until it hits the shoulder 24 ofthe overlap. These three parts hold the two halves together so that whenthe unit is put in the furnace, it is self-fixturing. In a tapered. pipethread, the use of a wire coil in the shape shown has the advantage thatthe ends of the wire are cut square as shown in FIG. 4.

Whereas the thread formation is shown as male threads in the drawings,it should be understood that the coil could be reversed so that the flatside 44 of the triangular cross section would be on the outside insteadof the inside and the coil slipped into an internal housing so as toform female threads. One of the advantages of coiling the spring of FIG.4 into the cylindrical coil rather than a taper is that the unassembledcoils will thereafter not have a tendency to nest and in assembly youwont have to discriminate between ends.

The end result is a ferrous product that does not require any castingand a minimum amount of machining the parts can be made by progressivedie stamping, transfer press stamping and spring coiling which insuresan inexpensive but reliable finished product.

While the preferred form and several variations of the invention havebeen shown and suggested, it should be understood that suitableadditional modifications, changes, substitutions and alterations may bemade without departing from the inventions fundamental theme.

I claim: 1. A method of making an electrical connecter for use withflexible conduit or the like, including the steps of forming a tubularbody section from sheet metal by pressing two portions of flat sheetinto oppositely arranged halves, bringing the two halves together withtheir edges in abutting contact to form the tubular body section,coiling a predetermined length of wire into a generally cylindrical coilwith the cross section of the wire being generally triangular so thatone side of the triangle will be on the inside of the resulting coil toform a generally smooth cylindrical inner surface on the coil to contactthe exterior of the body section, sliding the coil on the body section,providing a sufficient interference fit between the inside diameter ofthe coil and the outside diameter of the body section such that the coilwill be expanded slightly on the body section to exert a certain degreeof compression between the two halves of the body section, and brazingthe two halves of the body section together along their abutting edgesand, at the same time, brazing the coil on the body section with the twohalves and coil being self-jiggered due to the interference fit.

2. The method of claim 1 further characterized by and including the stepof tapering the portion of the exterior of the body section that thecoil is to be mounted on to a minimum diameter at least no less than theinside diameter of the coil, and allowing all turns of the coil toexpand as it is mounted so that the inside of the triangular crosssection of the wire will be in compression contact with the outside ofthe body section.

3. The method of claim 1 characterized in that the connecter is an elbowand further including the step of forming their edges in a lap jointover a substantial portion of their length.

4. In a connecter for joining flexible conduit to a work object, a bodysection made of sheet metal formed into a generally tubularconfiguration, the body section being made of two sheet metal halves, athread formation thereon including a wire coiled into a thread formbrazed to the body section, the wire being triangular in cross sectionwith the one side of the triangle being disposed on the inside of thecoil so as to provide a smooth inner surface in engagement with theexterior surface on the body section, the wire coil, in its free state,having an inside diameter slightly less than the outside diameter of thebody section such that when the coil is mounted thereon, itwill beslightly expanded providing an interference fit.

5. The structure of claim 4 further characterized in that the wire coilis mounted on a tapered portion on the body section with the smallestdiameter of the taper being slightly greater than the inside diameter ofthe coil.

6. A body member for use in joining a connector for flexible conduit toa terminus, including a tubular sheet metal sleeve with a thread formedon the exterior of one end for connection to a terminus, a polygonconnected on the outside of the sleeve adjacent the thread form with acylindrical interior therethrough, a nut on the other end of the sleeveforjoining a flexible conduit connector, and overlapping flanges betweenthe other end of the sleeve and the nut so that the nut will freelyrotate on the body member, the flange on the sheet metal sleeve being infixed spatial relationship to the polygon and thread form.

7. The structure of claim 6 further characterized in that the polygon ismade out of sheet metal and its cylindrical interior is braized to thesleeve.

. The structure of claim 6 further characterized in that the axis of thesleeve is straight.

9. The structure of claim 6 further characterized in that the axis ofthe sleeve turns through 10. A method of making a body member forjoining a connector forflexible conduit to a terminus, including thesteps of forming a tubular body section from sheet metal, positioning asheet metal polygon annulus with a cylindrical interior therethrou'gh onthe outside of the body section between the ends thereof, providing athread form on the exterior of the body section adjacent one endthereof, braizing the various parts together, thereafter positioning aninternally-threaded nut on the other end of the body section, anddeforming the said other end of the body section to retain the nutthereon.

11. The method of claim 10 further characterized in that the step offorming a tubular body section includes stamping a straight tubularpiece from a flat sheet.

12. The method of claim 10 further characterized in that the step offorming a tubular body'section includes positioning a sleeve on the saidother end thereof, and the step of deforming the said other end of thebody section includes deforming the sleeve so that it radially overlapsand retains the nut.

1. A method of making an electrical connecter for use with flexibleconduit or the like, including the steps of forming a tubular bodysection from sheet metal by pressing two portions of flat sheet intooppositely arranged halves, bringing the two halves together with theiredges in abutting contact to form the tubular body section, coiling apredetermined length of wire into a generally cylindrical coil with thecross section of the wire being generally triangular so that one side ofthe triangle will be on the inside of the resulting coil to form agenerally smooth cylindrical inner surface on the coil to contact theexterior of the body section, sliding the coil on the body section,providing a sufficient interference fit between the inside diameter ofthe coil and the outside diameter of the body section such that the coilwill be expanded slightly on the body section to exert a certain degreeof compression between the two halves of the body section, and brazingthe two halves of the body section together along their abutting edgesand, at the same time, brazing the coil on the body section with the twohalves and coil being selfjiggered due to the interference fit.
 2. Themethod of claim 1 further characterized by and including the step oftapering the portion of the exterior of the body section that the coilis to be mounted on to a minimum diameter at least no less than theinside diameter of the coil, and allowing all turns of the coil toexpand as it is mounted so that the inside of the triangular crosssection of the wire will be in compression contact with the outside ofthe body section.
 3. The method of claim 1 characterized in that theconnecter is an elbow and further including the step of forming theiredges in a lap joint over a substantial portion of their length.
 4. In aconnecter for joining flexible conduit to a work object, a body sectionmade of sheet metal formed into a generally tubular configuration, thebody section being made of two sheet metal halves, a thread formationthereon including a wire coiled into a thread form brazed to the bodysection, the wire being triangular in cross section with the one side ofthe triangle being disposed on the inside of the coil so as to provide asmooth inner surface in engagement with the exterior surface on the bodysection, the wire coil, in its free state, having an inside diameterslightly less than the outside diameter of the body section such thatwhen the coil is mounted thereon, it will be slightly expanded providingan interference fit.
 5. The structure of claim 4 further characterizedin that the wire coil is mounted on a tapered portion on the bodysection with the smallest diameter of the taper being slightly greaterthan the inside diameter of the coil.
 6. A body member for use injoining a connector for flexible conduit to a terminus, including atubular sheet metal sleeve with a thread formed on the exterior of oneend for connection to a terminus, a polygon connected on the outside ofthe sleeve adjacent the thread form with a cylindrical interiortherethrough, a nut on the other end of the sleeve for joining aflexible conduit connector, and overlapping flanges between the otherend of the sleeve and the nut so that the nut will freely rotate on thebody member, the flange on the sheet metal sleeve being in fixed spatialrelationship to the polygon and thread form.
 7. The structure of claim 6further characterized in that the polygon is made out of sheet metal andits cylindrical interior is braized to the sleeve.
 8. The structure ofclaim 6 further characterized in that the axis of the sleeve isstraight.
 9. The structure of claim 6 further characterized in that theaxis of the sleeve turns through 90*.
 10. A method of making a bodymember for joining a connector for flexible conduit to a terminus,including the steps of forming a tubular body section from sheet metal,positioning a sheet metal polygon annulus with a cylindrical interiortherethrough on the outside of the body section between the endsthereof, providing a thread form on the exterior of the body sectionadjacent one end thereof, braizing the various parts together,thereafter positioning an internally-threaded nut on the other end ofthe body section, and deforming the said other end of the body sectionto retain the nut thereon.
 11. The method of claim 10 furthercharacterized in that the step of forming a tubular body sectionincludes stamping a straight tubular piece from a flat sheet.
 12. Themethod of claim 10 further characterized in that the step of forming atubular body section includes positioning a sleeve on the said other endthereof, and the step of deforming the said other end of the bodysection includes deforming the sleeve so that it radially overlaps andretains the nut.